In this study, using classical molecular dynamics simulation approach, we have investigated the effects of nanoparticle dispersion and the intensity of filler and matrix interface attractions on the mechanical properties of buckyball reinforced polyethylene nanocomposites. The dispersion state of nanoparticles was studied by modeling nanoparticles either in a homogenously distributed form or in a clustered form. The quality of polymer-matrix interface was varied by altering the van der Waals interaction energy potential between the polymer and nanoparticle. Mechanical properties of the neat and nanocomposite systems were then evaluated using simulated hydrostatic tension tests. We have shown that the quality of nanoparticle dispersion can modify matrix morphology differently, which ultimately can alter the deformation and failure of the matrix material. We have demonstrated that the quality of nanoparticle-polymer interface affects the matrix morphology and the mechanical properties of nanocomposites. We have also shown that the enhancement in mechanical properties of nanocomposites depend solely on the extent of increase in overall matrix density, regardless the condition of the interface. (C) 2013 Elsevier Ltd. All rights reserved.